1. Field of the Invention
The present invention relates generally to internal combustion engines, and the means for supplying fuel and air to the combustion chambers of such engines. More particularly, it relates to carburetor engines, and to a method and apparatus for controlling the air of combustion supplied to the engine in response to engine rotational speed, whereby to maximize fuel utilization and minimize the production of pollutants.
2. Description of the Prior Art
In the conventional carburetor engine, the air of combustion is fed through the carburetor by the vacuum in the intake pipe. In such a conventional arrangement, however, particularly in the upper ranges of engine rotational speed, the ratio between the supplied fuel and the supplied air of combustion is too high, i.e., the fuel and air mixture is too rich. This leads to incomplete combustion of the fuel, and to an increased carbon monoxide content in the exhaust gas. Moreover, the utilization of the fuel is not optimum, since the unfavorable ratio between fuel and air of combustion leads to a high fuel consumption.
It has already been proposed to solve this problem by direct fuel injection. However, the technical expense required with this approach is considerable, and in particular the high pressure pumps and the control mechanisms therefor require a substantial expenditure in both labor and materials to manufacture and assemble. In addition, such highly stressed precision devices are particularly susceptible to operating trouble, and often have only a limited life.
There is need, therefore, for a new approach to solving the problem of having too rich a fuel and air mixture in carburetor engines at the higher engine speeds, and the present invention is intended to satisfy that need.